OSPF Sham-Link Support for MPLS VPN Configuration Tasks
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Cisco IOS Release 12.2(8)T
To create a sham-link, use the following commands starting in EXEC mode:
Verifying Sham-Link Creation
To verify that the sham-link was successfully created and is operational, use theshow ip ospf
sham-links command in EXEC mode:
Router1# show ip ospf sham-links
Sham Link OSPF_SL0 to address 10.2.1.2 is up
Area 1 source address 10.2.1.1
Run as demand circuit
DoNotAge LSA allowed. Cost of using 40 State POINT_TO_POINT,
Command Purpose
Step1 Router1# configure terminal Enters global configuration mode on the first PE router.
Step2 Router1(config)# interface loopback
interface-number
Creates a loopback interface to be used as an endpoint of the
sham-link on PE-1 and enters interface configuration mode.
Step3 Router1(config-if)# ip vrf forwarding
vrf-name
Associates the loopback interface with a VRF. Removes the IP
address.
Step4 Router1(config-if)# ip address
ip-address
mask
Reconfigures the IP address of the loopback interface on PE-1.
Step5 Router1(config-if)# end Returns to global configuration mode.
Step6 Router1(config)# end Returns to EXEC mode.
Step7 Router2# configure terminal Enters global configuration mode on the second PE router.
Step8 Router2(config)# interface loopback
interface-number
Creates a loopback interface to be used as the endpoint of the
sham-link on PE-2 and enters interface configuration mode.
Step9 Router2(config-if)# ip vrf forwarding
vrf-name
Associates the second loopback interface with a VRF. Removes
the IP address.
Step10 Router2(config-if)# ip address
ip-address
mask
Reconfigures the IP address of the loopback interface on PE-2.
Step11 Router2(config-if)# end Returns to global configuration mode.
Step12 Router1(config)# end Returns to EXEC mode.
Step13 Router1(config)# router ospf
process-id
vrf
vrf-name
Configures the specified OSPF process with the VRF associated
with the sham-link interface on PE-1 and enters interface
configuration mode.
Step14 Router1(config-if)# area
area-id
sham-link
source-address
destination-address
cost
number
Configuresthe sham-link on the PE-1 interface within a specified
OSPF area and with the loopback interfaces specified by the IP
addresses as endpoints. cost number configuresthe OSPF cost for
sending an IP packet on the PE-1 sham-link interface.
Step15 Router2(config)# router ospf
process-id
vrf
vrf-name
Configures the specified OSPF process with the VRF associated
with the sham-link interface on PE-2 and enters interface
configuration mode.
Step16 Router2(config-if)# area
area-id
sham-link
source-address
destination-address
cost
number
Configuresthe sham-link on the PE-2 interface within a specified
OSPF area and with the loopback interfaces specified by the IP
addresses as endpoints. cost number configuresthe OSPF cost for
sending an IP packet on the PE-2 sham-link interface.